The team has been expecting to announce its line-up next Monday, but main rival for the job Jean-Eric Vergne pre-empted any announcement by using Twitter to say that he had been dropped.

Any last question marks over Sainz were addressed after a strong performance while testing the Red Bull RB10 in Abu Dhabi earlier this week.

“Ever since I have been part of Red Bull’s Young Driver Programme, this has been my aim,” said Sainz. “And I want to thank Red Bull for putting their faith in me. I have had a very successful season in World Series by Renault this year and now I am looking forward to taking the step up to Formula 1. I tested for a day with Toro Rosso last year and I liked the atmosphere in the team. In the next few months I will be working hard on my preparation, ready to get in the cockpit in Jerez for the first test of next year. It will be nice to make my “official” debut as a Formula 1 driver in my home country!”

Team boss Franz Tost added: “With Carlos Sainz joining Max Verstappen in our driver line-up next year, we continue the Toro Rosso tradition of providing youngsters from the Red Bull Junior Driver Programme with their first steps in Formula 1. I have watched Carlos progress through the junior categories, always improving as he moved higher up the ladder, culminating in a well-deserved win in this year’s World Series. However, I also remember the day’s testing he did with us at Silverstone in 2013 in the STR8. He really surprised me and his engineers that day, with his mature approach and his speed.”

Probably a year in the weeds for STR next year. Sure, they’ll be days their two youngsters are exciting and fast, but I’d think they’ll be more days they are exciting and in the barriers and probably most days they’ll just struggle to find good setups and struggle to maintain good race pace. I wouldn’t expect much in the way of race-craft. But then STR’s only real job is to find & develop drivers for RBR, so probably one of them will emerge as a future RBR driver. Berger has his hands-full, if he’s still the driver coach for STR.